Just as background, this digital setup has been working successfully for
several weeks and as I mentioned in another post I've recently had over
170 contacts in both JT65/JT9 running 5 or 10W (my KX3 has 3rd third
party heatsink). The ALC was appropriately set based on information Don
provided several weeks ago but it was the first thing I checked. The
mic level was set for 5 bars ALC.
After the last problem, I checked all connections and setting and
everything seemed correct. The PSU was stable at 13.4V and VSWR sweep
on antenna did not show any problems. I connected rig to a power meter
and dummy load and brought up all the s/w. Things started working
again. I then put the radio through a 12 cycle CQ sequence at 10W.
Again all good. I reconnected the antenna and started attempting to
QSOs. PSKreporter showed I was getting out and then I worked two QSOs
without issue. However, on the third QSO, on the second transmission
block the TX power collapsed (KX3 TX light still red) I think midway
into the transmission - I halted TX on WSJT-X. I tried the tune
function on WSJT-X and while the KX3 TX indicator comes on there was no
TX power. ALC shows zero bars.
Thus, I would have to conclude the problem is an intermittent behavior
rather than setup issue. It seems to me the KX3 TX is shutting down in
response to some fault condition. PA temp is well below max, and no
other error messages are observed. Unlike when the unit powers down due
to high temp, the power setting remains at 10W. ALC shows zero bars.
While trying the tune function on WSJT-X after fault condition, I
increase mic gain and ALC bars start to briefly show and TX power
briefly flickers on power meter. However, within a second so the ALC
bars drop back to zero and so does the power. Increasing the mic gain
again results in similar behavior.
I switch all equipment off and call it a night. This morning, I bring
anything up again and the KX3 will not radiate power in digital mode
albeit the TX light is ON. Transmitting in FM the radio seems to be
working!
Again, thoughts would be greatly appreciated.
73's Gary K6YOA
That is a typical behavior when the KX3 (or K2 or K3) is not
provided with sufficient audio drive. It "power hunts".
Increase the soundcard audio output and/or the mic level to produce
4 bars with the 5th bar flickering on the ALC meter. Set the power
level with the power knob. Attempting to control the power level
with the audio drive will result in failure.
73,
Don W3FPR
On 7/12/2015 8:39 PM, Gary Hawkins wrote:
I'm seeing a odd problem working digital today with my KX3.
Sometimes when I go into transmit (power set at 5W) JT65_HF, my
Signalink shows PTT active (red light) , the KX3 shows PTT
active (red light) but no power is being radiated. Antenna
(dipole) has a near perfect match to the KX3. Power still shows
set to 5W on KX3. Problem remains if I switch from the antenna
to a dummy load. Osc and PA temp at 36 and 30C - PSU stable at
13.4V. When I try to transmit is DATA A mode (tune) power seems
to try to ramp up and then immediately falls away. Radio seems
to transmit fine in FM mode. What am I missing please?
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